Reaction device



May 21, 1957 JfH. BACH ETAL REACTION DEVICE Filed Nov. 8, 1954 Qmw SvREACTION DEVICE John H. Bach and Vaughn E. Peak, Hawthorne, and Karl W.Maier, Torrance, Calif., assignors to Northrop Airraft, Inc., Hawthorne,Calif., a corporation of Caliorma Application November 8, 1954, SerialNo. 467,332

15 Claims. (Cl. 89-1.7)

Our invention relates generally to reaction devices, and moreparticularly to a solid fuel reaction motor which is highly eicient forshort duration applications such as in spin launching rockets and thelike.

One specific example wherein the device of our invention is singularlyuseful is in the spin launching of rockets. The term rocket as usedherein for purposes of illustratng one application of our invention, isintended to include both guided and unguided self-propelledreactiondriven missiles.

By way of explanation; when any elongated missile is propelledlengthwise 'through the air, it has an inherent tendency to tumble, i.e., instead of proceeding along its trajectory with its longitudinalaxis parallel with the line of ight, this axis may rotate erraticallywith respect to that line of ilight. To reduce this tendency of amissile to tumble, and improve its stability over the flight trajectory,a means and method of spin launching, and spin stabilizing a rocketduring ight, is described, shown, and claimed in co-pending U. S. patentapplications: Serial No. 425,594, tiled April 26, 1954, by Edgar Schmuedet al., and Serial No. 425,595, also tiled April 26, 1954, by EdgarSchmued, wherein initial stabilizing spin is imparted to a rocket in thelaunching tube or bed during launching thereof so that the rocket willleave the launcher in a spinning condition, thereby providing gyroscopicstabilization of the longitudinal axis of the rocket upon entering theinitial acceleration phase of its flight trajectory. To this end, it isan object of our present invention to provide a spin motor of the solidfuel type having improved eiciency for short duration applications.

It is another object of our invention to provide a solid fuel typereaction device which can be adapted for spin launching rockets.

It is still another object of our invention to provide a spin motor forspin launching rockets, which can be quickly and easily recharged.

It is a still further object of our invention to provide a spin motor inwhich a charge of solid fuel is uniquely arranged in such a manner as toobtain optimum combustion efficiency.

Other objects will be readily seen as the specification proceeds.

Briefly, in one preferred embodiment thereof, as applied to spinlaunching a rocket, the spin motor of our invention comprises a spinmotor body adapted to be coupled with a rocket to be spin launched, asolid fuel charge supported and arranged in the spin motor body in sucha manner as to insure a high degree of combustion efficiency, and anignition system coordinated to ignite the spin motor charge and therocket propellant in proper sequence.

The principle, character, and preferred construction of our inventionwill be more clearly understood by referring to the appended drawingswherein:

Figure 1 is a side elevational View, partly in section and partlyfragmentary, showing one preferred embodi- 21,792,758 Patented May 21,1957 ment of our present invention coupled to a rocket in a launchingtube.

Figure 2 is a cross section View taken on line 2 2 of Figure 1 showingone novel means of suspension and arrangement of the solid fuel in thespin motor of our invention.

Figure 3 is a plan view of the brush assembly for igniting thepropellant charge indicated by arrow 4 in Figure 1, the housing beingcut away to show a preferred arrangement of the brushes.

Figure 4 is a perspective view of the rocket and spin motor of theprevious gures, with certain portions cut away to more clearly show thepreferred construction and arrangement of our present invention.

In Figure l a rocket 7 to be spin launched is shown positioned in arocket launching tube 9. The rocket 7 is provided with a rearwardlydisposed combustion chamber 10 containing a propulsion charge 11arranged in the usual manner; the gas from the propulsion charge 11,when ignited, being released through a number of nozzles 12 arranged andmounted at the rear end of the rocket to propel the rocket forward.

In accordance with our invention, the rocket 7 is initially spun, beforebeing propelled from the launching tube 9, by means of a spin motorassembly 14 which is mounted in the launching tube 9 rearwardly of therocket 7 as shown.

The spin motor assembly 14 of our invention generally includes couplingmeans for connecting the rocket and spin motor together, an exhaust orblast tube for carrying off the rocket propulsion charge gases, spinmotor ignition assembly, and spin motor, all of which will be identifiedand described in detail herein. In the present example, the couplingmeans is characterized by a number of conventional key slots 15 evenlyspaced around the circumference of flange 16 at the rear end of rocket 7as best shown in Figure 4; these slots 15 complementing and receiving alike number of keys 17 which are provided around the edge of the aredend 19 of a blast tube 20 which extends coaxially through spin motor 21and is coterminous therewith. The flared end 19 of blast tube 20, whencoupled with rocket 7, by keys 17 and key slots 15, completely surroundsand encloses the rocket nozzles 12 and thus ducts the releasedpropulsion gases through blast tube 20 and out the exit opening 22 asthe spin motor drives the rocket 7 to rotate prior to launching.

Spin motor 21 is rotatably mounted in the launching tube 9, andcomprises a cylindrical body 24 enclosing a combustion chamber 25 whichconcentrically surrounds the exterior blast tube 20. At the exhaust endof spin motor body 24, a flange 26 is formed normal to the axis of thebody 24, and a shallow land 27 precedes the ange 26; another land 27a ofthe same diameter being provided at the coupling end of motor body 24 toprovide bearing surfaces therefor.

Flange 26 extends beyond the end edge 29 of launching tube 9 to preventforward movement of the spin motor in the tube 9. The exteriorcircumference of the launching tube 9 is threaded to receive a retainingring 30 and exhaust shield 31; the motor 21 being thereby prevented fromaxial movement in the tube 9.

The exhaust end of spin motor body 24 and combustion chamber 25 isenclosed by a nozzle plate 32, the plate 32 being retained in positionby threaded portions 34 around the exterior of blast tube opening 22 andcentral opening 35 of nozzle plate 32. Spaced around the inner face ofnozzle plate 32 are a number of exhaust ports 36 which areAinterconnected with a number of tangentially directed exhaust nozzles37 on the rear face of the nozzle plate 32. It is preferred that theinterior ports 36 be sealed by frangible or rupturable seals 39, offoamedV plastic or other suitable material in the usual manner, for theobvious reason of preventing the entry of moisture or foreign matterthereinto.

In the combustion chamber 25, at the driving or coupling end of spinmotor body 24, an ignition charge 40` is formed in an annular ringaround blast tube 2Q and is sealed with a conventional fragibl'e seal41. A primer pellet 42 embedded in the ignition charge is, in thepresent example, red by electrical current conducted from a sourcethereof (not shown), such as a battery for example, through brushassembly 44y which is'enclosed in a housing 45 mounted on the exteriorperiphery of launching tube 9, as best seen in Figures l and 3. Y Y

The ignition of the spin motorcharge and toeliet propellant charge isachieved by contacting b/rlllshesl 46l and 47, respectively, with theexposed edgesfof annular tiring slipk rings 49 and 50 which are, in thepresent example, insulated by and embedded in a support member. 5.1Apreferablyy molded of a dielectric material Asuch as alphenolic resin orneoprene rubber for example, and mounted in launching tube 9 adjacent'toVtheforvvarif'lY end of spin motor body 24. inside the blast tube 20,support meinber 51 is encased in a protective heat resisting 'sheath 52,of a metal such as that used to. nzlakefthe blast tube 20, and forms anarrow streamlined bipodal member to reduce the amount of windresistance thereby in the ared throat of blast tube 20 as muchaspossible'l Of the two leg elements S4 and 54a of support member51,o`ne. element 54a encloses an insulated lead: 56VV connected at oneend thereof to tiring slipv ring 50; they other end terminating in a pin57 which is inserted in an electrical jack 59. housed in the rear end ofrocket 7. As shown in Figures l and 4, support member 51l extendsforwardly from its base to form a probe 60 which encloses andyinsulates, rocket propellant lead wire 56. Over the` endv of probe 60, asleeve 61 is tted to underlap thevsheath 52 and terminates at theforward end inV a button 62 having a detent groove 64 cut around theperiphery thereoffV The exhaust end of rocket 7 has a. coaxialreceptacle 66 therein to recess button 62 adjacent electrical jack 59.An annularv internal groove 67 extending around the inner periphery ofreceptacle 66 retainsl a split ring 69 which, when button 62 is recessedin4 receptacle 66, tits down into and around detent groove 6 4 to vholdthe button 6'2- in place and retain pin 57 in electrical engagementwithy jack 59. However, the button 62 may bewi'thdrawn from receptacle66 and pin 57 disengaged from electrical jack 59 by force exertedlongitudinally, either by movement of the rocket 7 forwardlyin the tube9, as when launched, or by withdrawing the spin motor assembly'21rearwardly fromV the4 tube 9 suchV as during servicel and installationoperations, for example. As shown, the wall. 70 of the detent groove 64nearest the end of button 62 is sloped forwardly to cam the split ring69out of the detent groove 6.4.'for release of the firing mechanism.The. outer end 71 of button 62 is also sloped, rearwardly from the outerend thereof, so thatthe split, ring 69 iscammed thereover when recessingthe button 62,in the receptacle` 66` to connect electrical pin 57 andelectrical jack 59, when the rocketV and spin motor arecoupled together.

In alignmentV with electrical pin 57, and retained in the opposite endof receptacle 66, is the jack 59. It will be noted that electrical jacl59 is embedded in dielectric plastic and insulated` from surroundingstructure by insulator sleeves 74.

An insulated lead, 75 isconnected, at one end thereof, in jack 59, theotherend,thereofextending coaxially and forwardly through rocketcombustion chamber 1010 propulsion charge primer pellet 77 and connectsinto primer cap`79., to ignite rocket lpropulsion charge 1v1 in theusual manner. Ground lead 81 is [connected *to the metal primer casing.d2l at. one end thereof; the other end being connected` to the metalsleeve74 around the lead jack 59, andy thus completes the electricalcircuit for firing the rocket propulsion charge.r

It can be Seen that-the-Operatisn of cartulina of. the

' argan@ ring circuit of the rocket 7 with the spin motor 21 is simplyand quickly achieved at the same time that the rocket 7 is installedy inthe launching tube 9 and moved into engagement with drive key slots 15and 17 in mesh; the electrical connection being made when button 62 isfully recessed in rocket receptacle 66 with split ring 69 securelyseated in annular detentV groove' 67 to electrically connect pin 57 injack- 59.

Rocket propellant ignition wire 7,5 conducts electrical current fromtiring slip ring 50. which malges continuous Contact with brush 47extended through aligned apertures 84 in the bottom of housing 45 andthough the Wall of launching tube 7, while the motor is spinning.V

The diameters of ring slip rings 49 and 50 should be suiciently smallerthank thek inside diameter of launching tube 9 so that an appreciableclearance space 85 is maintained between the contact or exposed edge ofthe rings 49 and 5 0 and the launching tube wall.

Brush 46, for firingl the spin motor 21 is maintained in` contact withthe edge of tiring slip ring 49 by a leaf spring 86 mounted in brushhousing 45 in the usual manner. Rocket tiring brush 46, in the samemanner as brush 47, is` extended through apertures 87 to contact ringslip ring 49, which is connected by insulated lead` 89 to primer pellet90, and ground brush 9 1 is contacted withy spin motor land 27g.

To improve the burning characteristics of the spin` motor fuel charge,and obtain the highest practicalr order of eiciency therefrom, wearrange the fuel in` such a manner as to provide a small web thicknessin india'idual grains andl therefore obtain a high ratio of initialcom.- bustion area to volumeof charge.

As shown in Figures land 2, the fuel for spin motor 21 isY uniquelyformed into tubular pellets or grains 95, in any convenient manner, andcut into desired lengths. These grains 95, after further forming, canthen be strung, or assembled, onto support wire-s4 (not shown) formedinto. individual rings or coils and thusbe supported thereby inthecombustion chamber 25` with all surfaces exposed to initialcombustion. The curved support wires, furthermore, expose the endsurfaces of the tubular grains, thereby increasing the initialcombustion area. of the fuel. In the particular embodiment of Figure l,however, annealed wire 97 of. suitable gage is helically wound into a,support for the tubular grains. of fuel. assembled thereon, and extendsthrough the combustion chamber 25, being maintained in a, positionconcentricV with the. axis of spin motor body 24 and. blast tube 20. Thediameter of the. fuel'grainsr95' is sized so that anappreciabieclearance between the wall of spin. motor. body 244l andblast tube 20 is uniformly maintained from one endV of combustionchambery 25 to the other.

Therearmost endl of the support wire 97 is suitably formed and anchoredaroundthe periphery of blast tube 20, being secured betweencircumferential ange 99 and the inner edge. of nozzle plate 37. For.easeof installing and reloading the fuel charge, they ignition charge40y is preferably retained in a light metal casing 100, the other end ofsupportwire 97, suitably formed, being-connected to the ignition chargecasing by edge rolling 101 around primer casing asshown.

While we have illustrated the helical support wirev 97 as beingixedat-either end in the combustion chamber-25, the, support wire 97could be freewheeling, with both ends` free, which would to. somedegreek tend to reduce centrifugal stresses on` the fuel grains.However, it has been` found that, with the ends ofthe support wire 97securely fastened toV xed supports, the response of the support wire torotation is so rapid that the individual coils will differonly slightly`with respect to relative position thereof during motion. However, in afuel arrangement as describedy above wherein theV tubular fuel grainsare supported on individual; rings of Wire, it is believed that 11o`appreciable diirenceia the effect o f the centrifugal stresses on thefuel grains would be encountered.

In the general fuel arrangement illustrated in the instant disclosure, anumber of distinct advantages will be noted by those skilled in the art.The relative proportions of the fuel grains and diameter of thecombustion chamber, which will be governed by the usual parameters, canbe adjusted to achieve the highest possible combustion eliiciencytherefrom.

Moreover, it has been found that the fuel grains, arranged and supportedin accordance with our present invention, have a much greater resistanceto breakaup than in prior known configurations and arrangements. It isfurther believed that the helical arrangement, due to its asymmetr' willnot induce the phenomena of extremely high peak pressures which areusually observed in symmetrical arrangements of fuel grains.

` While in order to comply with the statute, the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprises a preferred form of putting the invention into effect, and theinvention is therefore claimed in any of its forms or modificationswithin the legitimate and valid scope of the appended claims.

What is claimed is:

l. In a reaction device including a combustion chamber having a quantityof solid fuel therein; a fuel support comprising a plurality of Wirerings coaxially positioned along the extent of said combustion chamber,said fuel being concentrically formed around and supported by saidrings.

2. In a reaction device including a combustion chamber having a quantityof solid fuel therein; a fuel support comprising a helical coilcoaxially mounted in said combustion chamber, said fuel beingconcentrically formed around said helical coil and suspended thereby insaid combustion chamber.

3. In a reaction device including a combustion chamber having a quantityof solid fuel therein; a fuel support comprising a helical coil of wirecoaxially mounted in said combustion chamber, said fuel being tubularlyformed and strung onto said coil and suspended thereon in saidcombustion chamber.

4. In combination with a rocket launching tube and a rocket in saidtube, said rocket having a propulsion charge; means for spinning saidrocket about the axis thereof prior to ignition of said propellantcomprising a cylindrical motor body mounted to rotate about an `axis iin said launching tube, separable coupling means connecting one end ofsaid motor body to the exhaust end of said rocket, a combustion chamberin said motor body, a quantity of propellant grains in said combustionchamber, support means for suspending said propellant 'grains in saidYcombustion .chamber to expose a maximum area of initial burningsurfaces of said propellant grains, ignition means for igniting saidpropellant, tangentially directed exhaust means for releasing combustiongases from said combustion chamber to rotate said motor body, means forigniting said rocket propulsion charge during rotation of said motorbody, and means for bypassing propulsion gases from said rocket throughsaid motor body and out of said launching tube.

5. Apparatus in accordance with claim 4 wherein said propellant grainsin said combustion chamber are tubularly shaped, and wherein saidsupport means comprises a plurality of wire rings coaxially andconcentrically positioned in said combustion chamber, said tubularpropellant grains bein-g strung onto said rings and suspended thereby toexpose a maximum area of initial burning surface on said propellantgrains.

6. Apparatus in accordance with claim 4 wherein said propellant grainsin said combustion chamber are formed into curved tubes, and whereinsaid support means com.-

prises a coil of helically wound Wire coaxially and con# centricallypositioned in said combustion chamber and extended from one end of saidcombustion chamber to the other end thereof, said tubular propellantgrains being strung onto said wire and suspended intermediate the wallof said duct and said motor body to expose a maximum area of initialburning surface on said propellant grains.

7. In combination with a rocket launching tube and a rocket iin saidtube, said rocket having a propulsion charge; means for spinning saidrocket about the longitudinal axis -thereof prior to the ignition ofsaid propulsion charge comprising a cylindrical motor body mounted 4torotate about an axis in said launching tube, separable coupling meansconnecting one end of said motor body to the exhaust end of said rocket,a duct extending coaxially through said motor body, one end of said ductbeing open opposite the exhaust end of said rocket, the other end ofsaid duct being open opposite the exhaust end of said launching tube, acombustion chamber in said motor body and surrounding said duct, aplurality of propellant grains in said combustion chamber, support meansfor suspending said propellant grains in said combustion chamberintermediate said duct and the wall of said motor body to expose amaximum area of initial burning surfaces thereof, means for ignitingsaid propellant grains, tangentially directed exhaust means connectedwith said combustion chamber to release combustion gases therefrom torotate said motor body, and means for igniting said rocket propulsioncharge after said motor body has begun to rotate.

8. In combination with a rocket launching tube and a rocket therein,said rocket having a propulsion charge and exhaust nozzles for releasinggases from said propulsion charge to propel said rocket; means forspinning said rocket around the longitudinal axis thereof prior tolaunching, which comprises a cylindrical spin motor body mounted to spinabout an axis in said launching tube adjacent the exhaust end of saidrocket, a blast tube extending coaxially through said motor body, oneend of said blast tube being flared to extend around and enclose saidrocket exhaust nozzles, the other end of said blast tube being openadjacent the exhaust end of said launching tube, separable couplingmeans connecting said motor body to said rocket, an annular combustionchamber in said motor body and concentrically surrounding said blasttube, a plurality of tubular propellant grains in said combustionchamber, ra helically Wound support wire coaxially positioned in saidcombustion chamber and concentric with the wall of said motor body andsaid blast tube, said tubular propellant grains being strung onto saidsupport wire to expose a maximum area of initial burning surfacethereon, ignition means for igniting said motor propellant grains, aplurality of tangentially directed exhaust nozzles positioned aroundsaid blast tube and communicating with said combustion chamber to directcombustion gases therefrom to spin said motor body, and ignition meansfor igniting said rocket propellant charge while said rocket is beingspun, whereby said rocket is propelled from said launching tube in aspinning condition.

9. Apparatus `in accordance with claim 8 wherein said separable couplingmeans comprises a plurality of members mounted around said ared end ofsaid blast tube, and a plurality of members mounted on said rocketaround the exhaust end thereof, said members interlocking with eachother to couple said rocket with said spin motor body.

10. Apparatus in accordance with claim 9 wherein said friction means isa plurality of teeth on said rocket and extending around said rocketexhaust nozzles, and where in said flared end of said blast tube has aplurality of complementary teeth extending therearound meshing with saidteeth on said rocket to couple said rocket with said spin motor body.

ll. In combination with a rocket launching tube and a rocket therein tobe launched therefrom, said rocket having a propulsion charge andexhaust nozzles for releasing gasesmfrorn said propulsion eharge topropel said rocket mea-ns for spinning said rocket around thelongitudinal axis thereof prior to launching, which comprises acylindrical spin motor bodymounted to spin about an axis in saidlaunching tube adjacent the exhaust end of said rocket, a blast tubeextending coaxially through said motor body, one end of said' blast tubebeing ilared to enclose said rocket nozzles, coupling means on `saidrock-et and extending around said rocket nozzles, coupling meansextending around said ilaredend 0f said blast tube and di'sengageablycoupled with said coupling means on said rocket, an, annu-lar combustionchamber in said motor body and concentrically surrounding said blasttube, a pluralityV of tubular propellant grains in said combustionchamber,I a helicallyl wound' support wire coaxially positionedf in saidcombustion chamber and concentric with the wallY of said motor body *andsaid blast tube, said tubular propellant grains being, strung onto saidsupport wirel t o expose a maximum area of initial burning surfacethereon, a primer in said spin motor combustion chamber adjacent saidpropellant grains, a primer in said rocket adjacent said propulsioncharge., ignition means operable to ignite said spin motor propellantprimer, and ignition means operable while `said spin motor is spinningto ignite said rocket propulsion charge to thereby launch said rocket ina spinning condition.

l2. Apparatus in accordance with claim l1 wherein said ignition meansfor igniting said spin motor propellant primer and said ignition meansfor igniting said rocket propulso'n charge comprise a firstl c-ontactmember conducting electrical currentffrom a source thereof to re saidspin motor propellant primer, a second contact memberconductingelectr-ical current from a sourcethere'- of to fire saidrocketl propulsion charge while said spin motor and said rocket arespinning, and a groundl contact to said spin motor body andinterconnecting Isaid rocket propulsion charge primer and ignition meanstherefor, and saidV rocket propulsion charge and ignition4 meanstherefor;

13.` Apparatus in, accordance with claim 11 wherein said ignition meanscomprises a sheathed, dielectric 'support mounted. in saidY blast` tubeadjacent the ared end thereof, said support member extending through thewall of saidg blast tube and having thebase thereof joining the end' ofspin motor body adjacentthe exhaust end of said rocket, the other end,of said. support member extending into thev endy of, said rocket andterminating in ay disengageable rocket receptacle, therein, a firstannular conductor embedded iny said support member base and coaxial;with launching, tube. said conductor having al1 edge thereof exposedaround the exteriory periphery ofy said support member base,v anelectrical connection embedded in said supportV member connecting saidconductor to said spin motorpropellant primer, a brush contact extendedthrough the wall' of said launching tube and inv contact with saidannular conductor to conduct aow of electrical current from a sou-reethereof to re said spin motor propellant primer, a second annularconductor embedded in lsaid support member base adjacent said rstannular conductor and coaxial with said launching tube, said secondconductor having an edge thereof exposed around the exterior peripheryof said support member base, an electrical connection embedded in saidsupport member and connected at one end thereof to said annularconductor, the other end thereof terminating in a plug jack in saidrocket receptacle, said rocket receptacle being electrically connectedto said rocket propulsion charge primer, a second brush contactextending through the wall of said launching tube and in contact withsaid second annular conductor to conduct a tlow of electrical currentfrom a source thereof to tire said rocket propulsion charge primer whilesaid rocket is spun by said spin motor, thereby to launch said rocket ina spinning condition.

14. In a device of the character described; a fixed cyl inder, acylindrical motor body mounted to rotate about an axis within said fixedcylinder, means dening a corn-V bustion chamber in said motor body, theinterior Surface of `said cylindrical motor body forming the wall ofsaid combustion chamber, a plurality of tubular propellant grains insaid combustion chamber, a plurality of wire rings coaxiallyl positionedalong the extent of said com* bustion chamber, said propellant grainsbeing strung onto said wire rings and supported thereby between saidaxis of rotation and the wall of said combustion chamber to expose amaximum area of initial burning surfaces thereon, ignition means forigniting said propellant grains, and tangentially directed exhaust meansconnected with said combustion chamber to release combustion gasestherefrom to rotate said motor body.

15. In a -device of the character described; a fixed cylinder, acylindrical motor body mounted to rotate about an axis within said iixedcylinder, a combustion chamber in said motor body, a plurality of curvedtubular propellant grains, a helical coil of wire extending coaxiallythrough said combustion chamber, said propellant grains being strungonto said coil and suspended thereby in said combustion chamber toexposea maximum area of initial burning surfaces thereon, ignition means forigniting said propellant grains, and tangentially directed exhaustmeans. connected with said combustion chamber to release gases therefromto rotate saidmotor body.

Referencesv Cited4 in the'. tile of this patent UNITED STATESl PATENTS2,342,096 Zimmerman Feb. 1,5, 1944 Y 2,510,110 Hickman June 6, 19502,510,147 Skinner June 6, 1950 2,640,417 Bjork etal. June 2,l 1953FOREIGN PATENTS 2,497` GreatBritain` s of 185,8

116,430 Sweden May 2,1, 1946 120,158

